Burning Rocks

What kind of technological magic allows for this? Well, nothing too high tech really except for a special glass reservoir and some strategically placed holes and wicks to give the appearance of a flame floating on the rock. These lamps can burn using citronella oil which makes for a nice mosquito repellant when used in the backyard. We could see this looking good in an unused firplace or even as a collection on a table top or outdoor firepit.